Conventional apparatuses for calculating a fat burning amount (fat consumption amount) are disclosed in Japanese Patent Laying-Open No. 9-173500: “Training System”, Japanese Patent Laying-Open No. 7-84994: “Calculation Device for Consumed Fat Amount”, and Japanese Patent Laying-Open No. 6-331760: “Fat Consumption Measuring Equipment”.
In the training system of Japanese Patent Laying-Open No. 9-173500, a respiratory metabolism measuring device is used to experimentally calculate a fat burning rate for each of dozens of test subjects, and a fat burning ratio (%) is estimated from the results, using a statistic technique, in response to an elapsed time from the start of exercise.
With the consumed fat amount calculation device of Japanese Patent Laying-Open No. 7-84994, a fat consumption rate (%) is calculated in accordance with a table prepared based on the characteristics of the fat burning rate that it is in proportion to the exercise time and in reverse proportion to the exercise intensity.
With the fat consumption measuring equipment of Japanese Patent Laying-Open No. 6-331760, a fat consumption amount is calculated based on a fat consumption rate that is obtained from the exercise time and the oxygen amount necessary for exercise.
These conventional methods for calculating the fat burning amount, however, pose the following problems.
In Japanese Patent Laying-Open No. 9-173500, the fat burning rate is calculated based solely on the elapsed time from the start of exercise; it does not take account of a change of the fat burning rate due to a change of the exercise intensity. Thus, if an exercise intensity is increased/decreased during the exercise, an appropriate fat burning rate may not be applied, which would deteriorate accuracy in calculation of the fat burning amount.
In Japanese Patent Laying-Open No. 7-84994, the fat burning rate is calculated using the table prepared with the fat burning amount in reverse proportion to the exercise intensity. This again does not conform to the relation between the exercise intensity and the fat burning rate, or the characteristics that carbohydrate and fat burning rates are around 50% when the exercise intensity is up to 50-60% of the maximum exercise intensity and, when the exercise intensity exceeds the relevant range, the fat burning rate decreases along with an increase of the work load, and the fat burning rate becomes 0% with the exercise of the maximum work load. Thus, an error occurs in calculation of the fat burning amount.
International Patent Publication No. WO99/43392 discloses a method for controlling a load of an exercise machine employing an anaerobic threshold (AT), wherein the anaerobic threshold (AT) work load is obtained from characteristics of heart rate variability or the like. The publication, however, only discloses how the AT as an exercise level is obtained; it does not disclose how the AT is specifically utilized.
Herein, the heart rate variability is calculated by first detecting an electrocardiographic signal with an electrocardiographic sensor, calculating a heart rate from a detected peak value of the electrocardiographic signal, and utilizing a prescribed formula, the detail of which will be described later.
The present invention has been made taking notice of the conventional problems as described above, and its object is to provide a fat burning value calculating method, a fat burning value calculating apparatus and an exercise machine which can accurately calculate a fat burning rate and a fat burning amount of a person during exercise regardless of increase/decrease of the exercise intensity.